The 21-year-old has struggled to establish himself as a first-team regular for United and has had loan spells at Sampdoria, QPR and now Stuttgart.
Macheda joined Stuttgart on loan in January for the remainder of the season, and the German club have the option to buy him this summer.
The Italian, who has expressed an aspiration to one day return to the Premier League, is currently focused and happy in Stuttgart.
"My experience at Stuttgart is going very well," Macheda told calciomercato.it.
"I have immediately familiarised myself, and the relationship with my team-mates and coaches is great.
"In June the loan will end but I already have a verbal agreement with Stuttgart to extend my stay. If there is a chance to, I would be really happy to stay.
"My relationship with Sir Alex Ferguson is great and it's clear that I have always had the desire to return and play for the Red Devils.
"But returning now would not be good for my career because I need to play with continuity."
Macheda has also said he would consider a move back to Italy, and has been previously linked with a return to Lazio.
He added: "In the future I would like to go back to my country, and play in Serie A."